Manufacture of lubricating oil



Patented June 30, 1936 PATENT OFFICE MANUFACTURE OF LUBRICATING OIL Ernest F. Pevere, Beacon, N. Y.',

.Texas Company, New York, N. Y.,

.. of Delaware No Drawing.

' 6 Claims.

Thisinvention relates to the manufacture of lubricating oils, and particularly to mineral lubricating oils of improved character having an increased viscosity index. a ,In the production of high grade lubricating oils,

it is-well known that a relatively small change in the viscosity of the oil between temperatures of ay 100 F..and 210 F., is desirable. In other words, it is advantageous for the oil to have a relatively fiat viscosity-temperature curve, which means that the oil has a high viscosity index as defined by Dean and Davis in their article in- Chemical and Metallurgical Engineering, vol. 36, page 618. Improvement in lubricating oils has heretofore been accomplished by chemical refining, as by the use of selective solvents which are eifective in extracting or separating naphthenic constituents from paraflinic constituents,

thereby producing a resulting raflinate of in-,

creased viscosity index. This procedure involves expensive processing, and results in a reduced yield of finished oil.

The advantage of low pour point of a lubricating'oil has long been recognized. Paramn base and Mid-Continent lubricating oils have been subjected to dewaxing in order to reduce the pour point thereof. However, substantially complete removal of wax from such oils results in a lowering in viscosity index.

30 The present invention relates to the increase in viscosity index of naphthene base or paraffin base lubricating oils, by the addition thereto of a small proportion of a material which is active to increase the viscosity index without objectionably affecting other desirable properties thereof. More particularly, the present invention relates to the pro-e duction of an improved lubricating oil of this type having increased viscosity index, by the addition thereto of a controlled proportion of sweatings from oxidized paraflin wax, or semi-liquid products of the character found inv oxidized parafiin wax.

I am aware that it has heretofore been proposed to add about 2% to 3% of oxidized paraflin wax to a mineral lubricating oil for the purpose of increasing the oiliness or lubricating value thereof. The present invention is distinguished from this practice, in that it relates to the entirely different function of increasing viscosity index, and is accomplished by the use of a different proportion range of active materialsseparated from oxidized paraffin wax. J

The material employed in accordance with the present invention comprises the low melting products, containing acids, esters, lactones and other assignor to The a corporation Application May 28, 1934, Serial No. 727,985

compounds, which are in large'part separated from the higher melting unoxidized paraflin wax. Such separation may be conveniently accomplished by the well known process of sweatin similar tothat commonly practiced in the removal of oil from crude paraflin wax. The semiliquid products or sweatings thus obtained are substantially free from unoxidized parafin wax, or do not contain more than a negligible proportion of such unoxidized wax. This material is added to a mineral lubricating oil in a controlled proportion, generally about 5% to 15% by weight. In such proportions, it is effective in raising the viscosity index of a naphthene base oil about -60 points and of a paraflin base oil about 10-30 points. r

Preferably a specially prepared oxidized paraiiln wax, such as that disclosed in the U. S. patent to Gallsworthy No. 1,909,945, is employed. As set forth in the patent, a charge of paraffin wax, for example crude scale wax having a gravity of between 48 and 50 A. P. I. at 130 F., is placed in an enameled or aluminum vessel which is preferably jacketed or otherwise fitted to permit heating orcooling of the contents. The vessel is also fitted with an air distributor, preferably located near the bottom, through which air may be introduced in fine streams to promote intimate contact of the air with the oxidizing mass. If the vessel is well insulated, the heat developed by the oxidation will be sufiicient to maintain the charge at the proper temperature, once it has been brought to that temperature by outside means such as a steam coil. The charge of wax may be heated to a temperature between. 260 and 335 F. and air may be introduced in sufiicient quantity to maintain the desired temperature. The most satisfactory temperature range for the oxidation has been found to be about 315 to 320 F. The oxidation is allowed to proceed until the batch attains a gravity of 33 to 35 A. P. I. By carrying out the oxidation in this manner, a material is produced having a low acid value while containing a relatively large amount of saponifiable bodies or esters. Moreover, the oxidizedmaterial is substantially free from red gumjwhich is that material insoluble in naphtha, for example an 86 B. gasoline. The lower melting materials or semi-liquid products of such an oxidized wax are found to be particularly valuable for purposes of the present invention.

As an illustrative example of the invention, the following data is given. A charge of about 2300 pounds of crude scale wax was placed in an enameled vessel, and after preliminary heating air was introduced to maintain a temperature of about 320 F. The oxidation was continued for a period of about 16 hours or until the batch of oxidizing wax indicated a. gravity of about 34 A. P. I at 130 F; The finished material was found to be of excellent color and showed no traces of gummy material when mixed with 86 B. gasoline to form a 10 solution. The oxidized wax had an acid number of about 26 and a total saponification value of about 93, gave a ratio of neutral saponification value to acid value of around 3 to 1. Generally, a ratio of over 2 /2 to 1 is desired.

The resulting oxidized material was then subjected to sweating at -100 F., and separated into approximately of semi-liquid sweatings and A; of solid waxy material. The sweatings so obtained had approximately the following tests:

Gravity, B 25.5 Viscosity at 100 F SU 205 Pour, F Neutralization No 25.8 Saponification No 129 As an example of the effect of the addition of sweatings from' oxidized paramn wax of this character to a mineral lubricating oil, the following tests of a typical naphthene base oil before and after the addition of 10% of the sweatings thereto, are given below:

5: Naphthene thene Tests on sweatings base oil f sweatings Gravity, A. P. I 19.0 19. 7 Flash. F 385 385 Fire, F 440 435 535 459 0 44. 5 Calculated 141 from Dean and Davis formulae.

As a further example, tests on a paraflin base dewaxed lubricating oil before and after the addition of 10% of the same sweatings thereto are given below:

Obviously many modifications and variations of the invention, as hereinbefore set forth, may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

I claim:

1. A mineral lubricating oil of relatively higher viscosity index comprising a petroleum lubricating oil of relatively lower viscosity index and a Saybolt viscosity at F. in excess of 100 admixed with about 5% 15% by weight of the semi-liquid products of the character found in oxidized paraffin wax and consisting of only a minor proportion of acids and a major proportion of other saponifiable compounds including esters, such products containing substantially no unoxidized wax.

2. A mineral lubricating oil of relatively higher viscosity index comprising a petroleum lubricating oil or relatively lower viscosity index and a Saybolt viscosity at 100 F. in excess of 100 admixed with about 5%-15% by weight of sweatings from oxidized paraflin wax.

3. A mineral lubricating oil of relatively higher viscosity index comprising a petroleum lubricating oil of relatively lower viscosity index and a Saybolt viscosity at 100 F. in excess of 100 admixed with about 5%-15% by weight of the semi-liquid products of the character found in oxidized paraifin wax which has been oxidized in such manner as to contain only a minor propor-- tion of unoxidized paraflin wax and substantially no red gum, and to have a ratio of saponification value to acid value of over 2 to 1, such semiliquid products containing substantially no unoxidized wax.

4. A mineral lubricating oil of relatively higher viscosity index comprising a petroleum lubricating oil of relatively lower viscosity index and a Saybolt viscosity at 100 F. in excess of 100 admixed with about 5%-15% by weight of sweatings from oxidized parafiin wax which has been oxidized in such manner as to contain only a minor proportion of unoxidized paraflin wax and substantially no red gum, and to have a ratio of sapcnification value to acid value of over 2 to 1.

5. A mineral lubricating oil of relatively higher viscosity index comprisng a petroleum lubricating oil of relatively lower viscosity index and a Saybolt viscosity at 100 F. in excess of 100 admixed with about 5%--15% by weight of sweatings from oxidized paraflin wax having an A. P. I. gravity of about 33-35 at F.

6. A mineral lubricating oil having a viscosity index in excess of 30 and a pour point less than 0 F., comprising a blend of a naphthene base lubricating oil normally having a viscosity index of around 0, a Saybolt viscosity at 100 F. in excess of 100 and a pour point less than 0 F., with about 5%15% of sweatings from oxidized paraflin wax.

ERNEST F. PEVERE. 

